"Kevin Grittner" <kgrittn@mail.com> writes:
Alejandro Carrillo wrote:
I try to do a function that let know which rows are deleted in a
table using the xmax !=0
That's not something you're going to have much luck with by using
plpgsql to try to parse heap pages.
No, because xmax being nonzero doesn't prove much: the row might be
updated/deleted, or it might only have been locked by SELECT FOR UPDATE,
or it might be perfectly fine because the updating transaction rolled
back. You could get a limited amount of information by checking the
hint bits in t_infomask, but if the hint bits aren't set you won't know
what the row's state is.

You'd really need to do this in C using the tqual.c functions for the
results to be trustworthy.

I'm a bit surprised that contrib/pageinspect doesn't have a mechanism
for pulling out only committed-good heap tuples...

    regards, tom lane

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postedJan 20, '13 at 1:46p
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